1. Field of the Invention
This invention relates to testing tires for uniformity and, more particularly, to a method and apparatus for automatically feeding tires to a test spindle and there testing them for uniformity.
2. Description of the Prior Art
As manufactured, tires are not always uniform in their distribution of materials throughout their masses. Tires with a lesser degree of uniformity will induce greater vibrational and acoustical disturbances into the vehicles on which they are utilized. Conversely, tires with a greater degree of uniformity will induce lesser or no disturbances into the vehicle on which they are utilized and thus provide a superior ride. Tires manufactured with an unacceptable degree of non-uniformity may be reworked as through buffing or grinding or the like prior to sale and use. In any event, the manufacturer must continuously remain cognizant of the quality of his manufactured tires, always trying to improve them, in order to maintain the quality of his products in the market place and retain a competitive edge.
Manufactured tires are normally tested on machines to determine their uniformity. Efforts are continuously being made to improve tire uniformity machines which may more accurately and conveniently test and grade tires to determine their degree of uniformity or non-uniformity. The most common type of tire uniformity machine in commercial use today requires the manual placement of a tire, supported on a rim, onto a rotatable spindle. An adjacent roadwheel is rotated in contact with the test tire at speeds and loads representative of those which occur on automobiles in service. During testing, vibrations caused by non-uniformities or irregularities in any test tire are induced into the roadwheel. A transducer coupled with the roadwheel may sense and record the vibrations of the roadwheel. Such roadwheel vibrations represent tire nonnon-uniformity since vibrations of the roadwheel correspond with vibrations of the tire.
Uniformity machines may be rendered more efficient by several techniques. First, the coupling of the transducer to a test spindle rather than to the roadwheel will preclude the enormous inertia of the roadwheel from dampening out much of the vibrations intended to be measured. Second, the placement of the test tire with its supporting rim onto the test spindle has been found to be more accurate and less conducive to error when done automatically rather than when such placement is done manually by an operators Third, the use of specially designed precision rims and spindles at the test station can reduce or eliminate extraneous vibrational signals normally caused by conventional rims and spindles. Reducing or eliminating such extraneous vibrational signals results in the transducer sensing only those signals caused by tire non-uniformity for more accurate grading of tires as intended.
In this last regard, the prior art discloses many types of rims and spindles as well as a wide variety of techniques for coupling such rims to spindles for various purposes. A common purpose for such coupling is so that the manufactured tire might be trimmed, buffed, trued or the like for rendering the tire more uniform in its shape. Note, for example, U.S. Pat. Nos. 2,321,936 to Pollock; 2,759,508 to Tobey; 2,868,291 to McMahan; 2,918,116 to Mooney; and 3,556,194 to Farrington. Similarly, such coupling techniques might be utilized for supporting a tire for rotation during a recapping or retreading operation. Note for example, U.S. Pat. Nos. 2,116,512 to Ericson, et al and 3,614,969 to Breiner. The prior art discloses many other additional techniques and devices for supporting a rim on a spindle for various other purposes. Such purposes include tire building, tire changing, tire balancing, tread building, or the like. Note for example, U.S. Pat. Nos. 2,000,036 to Renfro; 2,081,402 to Krema; 2,270,657 to Kraft; 2,334,606 to Castiglia; 2,481,926 to Henderson; 2,603,267 to Simpson; 2,973,791 to French; 3,219,078 to Wright; and 3,238,982 to Darr. Lastly, the prior art also disloses devices for supporting a pneumatic tire on a spindle through a rim wherein the device includes apparatus for automatically inflating the tire. Note, for example, U.S. Pat. Nos. 2,960,130 to Smyser and 3,291,171 to Lehmann.
None of these prior art patents or commercial devices teach or suggest the efficient, accurate, convenient, and economical machine and method as described herein. Known methods and apparatus for testing the uniformity of tires are simply lacking in one regard or another.
As illustrated by the great number of prior patents and commercial devices, efforts are continuously being made in an attempt to more readily test tires for uniformity. None of these prior art efforts, however, suggests the present inventive combination of method steps and component elements arranged and configured for testing the uniformity of tires as disclosed and claimed herein. Prior methods and apparatus do not provide the benefits attendant with the method and apparatus of the present invention. The present invention achieves its intended purposes, objectives and advantages over the prior art devices through a new, useful and unobvious combination of method steps and component elements, through the use of a minimum number of functioning parts, at a reduction in cost to manufacture and operate, and through the utilization of only readily available materials and conventional components.
These objects and advantages should be construced as merely illustrative of some of the more prominent features and applications of the present invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other objects and advantages as well as a fuller understanding of the invention may be had by referring to the summary and detailed description of the preferred embodiment of the invention in addition to the scope of the invention as defined by the claims taken in conjunction with the accompanying drawings.